Helpful guide to buying a second card off ebay for SLI and CF.

[MkGriff1492]

Had some time so decided to write up this guide from my experience. Hope it helps someone out.

So Far my personal experience with Crossfire with two Gigabyte 7950 3gb cards have been good. When CF has the right drivers it runs very well and smooth. Haven't had any issues with BF4 or any other games that are supported. For the last couple months Ebay has been full of ATI cards used for mining. A lot of the small miners are unloading there cards on Ebay, for example I got my card for $100 dollars I paid $280 in 2013. GPU's are no longer the go to for bitcoin mining since ASIC hardware is now available. Litecoin mining using even more power then bitcoin increasing the overhead to run a mine. If your a gamer like me you probable had to pay a little extra for your card over the last couple years because of miners. They where buying cards in bulk and creating a video card ram shortage starting in early 2013. So now it's time for some payback since they made us overpay for our cards. But this does not come without it's risks. These card were likely run 24 hours and have been exposed to a lot of heat. I've listed some steps I used when buying my card.

1. If they post the serial number look it up. From the serial number you can tell the year
and week the card was manufactured. From this you can estimate the amount of usage. Also you can make sure you get the most updated card. For example your card runs at 1000 mhz at default but another might be a different version and run at 900. If you get a 900mhz card the 1000mhz will be down clocked during CF to 900mhz. So you will either have to flash the bios of the 900mhz to the updated 1000mhz bios or overclock it.

2. Inspect the pictures of the back pci board thoroughly. The pci board is the most important part of the card. You will see some slight discoloring but you shouldn't see a lot.

3. First thing test the card as soon as you get it. Check for artifactiong from bad vram. Us HWMonitor to look at it's temperatures to make sure temperature isn't causing it. It will run a little hotter then your first card but that can be fixed.

4. This is the most important replace the thermal paste and thermal pads. Mining dries out the paste and it's a good idea to replace the pads also.

5. Check the fans. Mining kills the GPU Fans! If there just making a little noise use sewing machine oil. Sewing machine oil is non-conductive and safe to use. GPU fans are not easy to oil there magnetic. Since you need to replace the thermal paste I recommend taking the fans out putting them upside down and putting 2 drops in the little gap around the fan. If the fan is rattling it will most likely die. On the back of the fan there's a model # look it up then determine how many 3 pin and 2 pin fans you need. You will have to use Ebay once again for this. I replaced all 3 fans on my card but was only really having trouble with one.

Overall there are some risk involved but everything rewarding does. Ebay has buyer protection and they really favor the buyers. So if the vram is bad or card does not work they have to give you your money back. As long as the card isn't artifacting the vram should be good. So run some graphic tests and simple game on just the Ebay card at first. Overall GPU's can take a beating and handle heat very well even in excess of 80c. Nothing against miners but if you can pick up a cheap card at their loss then why not. Even if it's just to mess around with for a couple of games.

 

[MkGriff1492]

How to Remove Heat Sink from GPU.

1. Remove 3 pin power connector if possible. It's very fragile and will break very very easily.

2. Heat up the card to loosen the hold of the thermal paste from the GPU. You can use a hair dryer if its putting up a fight. Try to move the heat sink very slight side to side. Lift very slightly where you see thermal pads on the vram. Thermal pads are sometimes sticky on both sides. You must be very careful of capacitors and the 3 pin. You can easily destroy your card if your not careful.

3. Once you loosen the heat sink the thermal pads should release from the vram and stick to the heat sink. They sometimes don't have to be replaced but I recommend you replace them. Thermal pads are used anytime there's a gap that needs to be connected to a heat sink. They are used everywhere from laptops to GPUs and perform the same function as thermal paste.

4. The hardest part of removing your heat sink if doing it for the first time. It's a learning process that can't be rushed but must be taken slowly.